Again thank you for the top advice . I've left it a few days before replying to see what effect those changed had on his behaviour.
I've upped his warm side to 32 degrees , this has also increased his cool side to almost 25 degrees. To answer the question about light. My office is in a south facing room in my house , plenty of natural light. Upping the temps he moved to his cool side for 2 days before returning to his warm side. I haven't seen him since returning to his warm hide. Normally I would see a head at some point. Even on an evening he is firmly hidden in his hide. (I suspect he is in shed), but i am not going to disturb him to find out.
Interestingly ( nor not) but when he is "Feeding" mode , one slight sniff of food and he is out and about. I've never actually fed him while he is even partially in his hide. Even now , he does come out very quickly when food is around I just don't get that strike.
The ASF are available from my local pet shop (They are just referred to as Multi mice) and I've tried them before (They have a very very distinctive smell). Hopefully he will shed soon , when do you think I should try to fed him again ?
Thank you for all the advice.
Chris